Apple artificially limits the internal bus speed
of its mini's to make them less competitive
with the iMac and MacPro. The MacBooks
are also artificially limited. You'll need to
purchase a 5.1 mini to get a Link Speed
of 6 Gigabits per second with a Negotiated
Link Speed of 3 Gigabits per second.

People who paid several thousand dollars
for a MacBook Pro and learned their new
SSD runs at a slower speed than expected
aren't happy about it. Few paid attention
to this but now that SSD's are more affordable
Link Speed has become important. At least on
paper, for most. I wouldn't be happy about it
either. The way I use my mini though, it wouldn't
matter._________________2011 Mac mini 2.7 GHz i7 with
16GB RAM, Samsung 512GB SSD
MacBook Pro 17" 2.5GHz
MacBook AIR 11 Inch
Mac mini, Model 1.1, 2.33 GHz C2D Proc